SAN FRANCISCO— The Center for Biological Diversity called on Gov. Jerry Brown on March 26 to investigate why dozens of legally required notices of a dangerous oil industry practice called “acidizing” are missing from the reporting website of a California agency responsible for collecting information on hydraulic fracturing, acidizing and other risky techniques used in oil and gas extraction. Acidizing uses dangerous acids to dissolve underground rock formations and release oil and gas.

In a letter to the governor (see PDF), the Center pointed out that notices for more than 50 known occurrences of acidizing in Los Angeles and Orange counties do not appear on the Division of Oil, Gas, and Geothermal Resources’ website. Failing to notify the public about acidizing violates a state law signed last year by the governor, putting communities at risk.

“State regulators are apparently leaving Californians in the dark about dangerous oil production methods being used in their communities,” said Hollin Kretzmann, a Center attorney. “It’s inexcusable that the state failed to inform the public about more than 50 toxic acidizing events, which produce air pollution that threatens our health. How many other instance of acidizing and fracking are illegally going unreported in our state?”

Acidizing uses high quantities of hydrochloric and hydrofluoric acids in combination with other harmful chemicals to dissolve oil-bearing formations underground. These acids, because of their toxicity and corrosiveness, pose a safety risk to surrounding communities that may be exposed through leaks, spills, accidents, or air evaporation.

The division began requiring oil and gas well operators in January to file notices at least 10 days in advance of using an unconventional extraction method such as hydraulic fracturing or acidizing. So far this year, 50 notices have been posted to DOGGR’s website. All of these notices are for well stimulation in Kern County.

Yet reporting data from the South Coast Air Quality Management District, which requires similar reporting, shows that 57 instances of acidizing occurred during the same period in Los Angeles and Orange counties. None of these occurrences are reported on the Division’s website.

That gap suggests that other dangerous well-stimulation methods, including fracking, may also be going unreported. Fracking, also known as hydraulic fracturing, involves injecting hundreds of toxic chemicals into the ground at extremely high pressure to fracture geologic formations and increase the flow of oil or gas to the surface.

A recent Center report found that acidizing and fracking operations employed 12 dangerous “air toxic” chemicals hundreds of times in the Los Angeles Basin over a period of a few months.

“It’s unclear whether the state oil regulators are holding back information about dangerous production techniques or operators are violating the reporting requirements,” Kretzmann said. “But either way, Gov. Brown needs to get to the bottom of this and correct the situation immediately.”